<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      border: 2px solid yellowgreen;
    }

    .box1 {
      height: 200px;
      width: 200px;
      background-image: linear-gradient(to right top, orange, red, black, blue);
    }

    .box11 {
      height: 200px;
      width: 200px;
      background-image: linear-gradient(20deg, orange, red, black, blue);
    }

    .box2 {
      height: 200px;
      width: 200px;
      background-image: radial-gradient(circle, red, black, pink);
    }

    .box22 {
      height: 200px;
      width: 400px;
      background-image: radial-gradient(ellipse, red, black, pink);
    }
  </style>
</head>

<body>
  <div class="box1"></div>
  <div class="box2"></div>
  <div class="box11"></div>
  <div class="box22"></div>
</body>

</html>